This invention relates to a process which uses an acidic medium containing nitric acid.
There are many processes which use acidic mediums containing nitric acid, i.e. nitrate containing acids. Such processes are, for example, leaching, etching and pickling. Acidic effluents are produced by such processes and these effluents have to be neutralised. This requires the use of substantial quantities of alkali. Also, the consumption of nitric acid is high. A further problem with these processes is the emission of nitrogen oxide gases which give rise to environmental problems.